THE AMPHIOXUS AS THE ANCESTOR OF MAN. 99 



known to us, the whole subject of the development of 

 the Vertebrate tribe, and thus of our own race, would be 

 enveloped in an impenetrable veil. The accurate anatomical 

 and ontogenetic knowledge of the Amphioxus, attained 

 during the last few years, has alone pierced that heavy veil, 

 formerly supposed to be impenetrable. If the Amphioxus is 

 compared with the developed Man or any other of the 

 higher Vertebrates, a great number of striking dissimilarities 

 will be seen. The Amphioxus has no specialized head, no 

 brain, no skull, no jaws, no limbs ; it is without a central- 

 ized heart, a developed liver and kidneys, a jointed vertebral 

 column ; every organ appears in a much simpler and more 

 primitive form than in the higher Vertebrates and in Man. 

 (Cf. Table X., vol. i. p. 46 6.) And yet, in spite of all these 

 various deviations from the structure of other Vertebrates, 

 the Amphioxus is a genuine, unmistakable Vertebrate ; 

 and if, instead of the developed Man, the human embryo 

 at an early period of its Ontogeny is compared with 

 the Amphioxus, we shall find perfect parallelism between 

 the two in all essential points. (Cf. Table IX., vol. i. p. 465.) 

 This highly important parallelism justifies the conclusion 

 that all the Skulled Animals (Cvaniota) have descended 

 from a common primaeval parent-form, the structure of 

 which was essentially that of the Amphioxus. This parent- 

 form, the earliest Primitive Vertebrate, possessed the 

 peculiar characters of the Vertebrates, and yet was without 

 all those important peculiarities that distinguish the Skulled 

 Animals from the Skull-less. Although the Amphioxus ap- 

 pears peculiarly organized in many respects, and although 

 it may not be regarded as an unmodified descendant of the 

 Primitive Vertebrate, yet it must have inherited from the 



